Dental and orthopedic densitometry modeling system and method

ABSTRACT

A dental and orthopedic densitometry modeling system includes a controller with a microprocessor and a memory device connected to the microprocessor. An input device is also connected to the microprocessor for inputting diagnostic procedure parameters and patient information, which may include a pre-existing densitometry model. X-ray equipment including an X-ray source and an X-ray detector array are connected to a positioning motor for movement relative to a patient&#39;s dental or orthopedic structure in response to signals from the microprocessor. The output consists of a tomographical densitometry model. A dental/orthopedic densitometry modeling method involves moving the X-ray equipment across a predetermined scan path, emitting dual-energy X-ray beams, and outputting an image color-coded to correspond to a patient&#39;s dental or orthopedic density.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to dental and orthopedicdiagnosis and treatment, and in particular to a densitometry modelingsystem and method.

2. Description of the Related Art

The field of dental diagnostics is generally concerned with locatingpathologies in the dental structure, i.e. the teeth and surroundingtissue and bone. Three of the most common pathologies are: 1) cariesassociated with decay; 2) fractures; and 3) apical abscesses. The systemand method of the present invention are primarily, but not exclusively,concerned with detecting these pathologies and with orthopedics.

Early detection of dental pathologies is very important in minimizingdamage. Conventional diagnosis procedures are generally performed usingdental X-rays (both fixed beam and scanning beam), explorers, and otherconventional equipment.

Incipient caries, particularly those located beneath the enamel surface,often go undetected with conventional equipment. When such caries arefinally found, considerable damage to tooth structure may have alreadyoccurred. Subsurface, incipient caries are located almost entirelywithin the enamel layer of the teeth. They are sometimes referred to as“smooth surface” caries and are particularly difficult to locate usingconventional diagnostic equipment and procedures. By the time suchincipient caries are located, the extent of the damage is often 17% to23% greater than it would appear to be on a conventional X-ray negative.

Dental fractures can result from bruxism (teeth grinding), trauma, etc.Dental structure which is weakened by various causes, such asdecalcification, is particularly susceptible to fractures. Fractures canassume various configurations, including craize line patterns. Fracturepatterns and configurations can be particularly difficult to locateusing conventional X-ray equipment and procedures. For example,fractures which are generally parallel to the X-ray beam are oftenundetectable on an X-ray negative. Undetected, and hence untreated,fractures can provide direct paths through the enamel layer of the teethwhereby bacteria can invade the dentin and pulp layers. Pathologies inthe dentin and pulp layers are often associated with considerable painand tooth loss.

Apical abscesses comprise yet another dental condition which can bedifficult to diagnose with conventional equipment, particularly in theearly stages. Advanced apical abscesses can cause considerable painbecause they involve the neurovascular bundles located in the rootcanals. Early detection of apical abscesses can lead to appropriate,early-stage treatment, thus avoiding advanced disease processes withresultant pain, swelling, and/or space involvement which left untreatedcould ultimately result in death.

Tomography or sectional radiography techniques using scanning X-raybeams have previously been employed for dental applications. Forexample, U.S. Pat. No. 4,188,537; U.S. Pat. No. 4,259,583; U.S. Pat. No.4,823,369; U.S. Pat. No. 4,856,038; and U.S. Pat. No. 5,214,686 allrelate to dental X-ray diagnosis utilizing scanning techniques and areincorporated herein by reference.

In the medical field, densitometry procedures are used for measuringbone morphology density (BMD) by utilizing scanning X-ray beamtechniques. Examples are shown in U.S. Pat. No. 5,533,080; U.S. Pat. No.5,838,765; and U.S. Pat. No. Re. 36,162, which are incorporated hereinby reference. Medical applications of densitometry include the diagnosisand treatment of such bone diseases as osteoporosis.

The availability of relatively fast computers with large memories atreasonable costs has led to the digitalization of X-ray images formapping BMD models in various formats. For example, BMD images use colorto identify varying densities. Digital BMD patient models are also usedfor comparison purposes with standard models and with patients' ownprior BMD histories. Age correction factors can be applied to patients'models for diagnosing and monitoring the onset and progress of suchmedical conditions as osteoporosis and the like. The present inventionutilizes such densitometry modeling and mapping techniques for dentalapplications.

In addition to pathology detection and diagnosis, the present inventionhas applications in monitoring osseointegration. Osseointegration occursat the interface between bone structures and prostheses, such asimplants and replacement joints. For example, dental implantsosseointegrate with patients' dental structure. The application oftomographical densitometry techniques to osseointegration monitoring canprovide the dental or medical practitioner with important information inevaluating the effectiveness of implant procedures.

Heretofore there has not been available a system or method for applyingthe technology of densitometry to dental and medical applications suchas the detection of caries and decalcification and the monitoring ofosseointegration in connection with dental and medical prostheses.

SUMMARY OF THE INVENTION

In the practice of the present invention, a dental and orthopedicdensitometry modeling system utilizes a controller with a microprocessorand memory. An input device inputs data to the microprocessor forcontrolling the operation of the modeling system and for providing adatabase including densitometry parameters for comparison with apatient's densitometry model. The controller controls the operation ofX-ray equipment, which is adapted for scanning patients' dental andorthopedic structures along preprogrammed scan paths. The X-ray outputis processed by the microprocessor for creating a densitometry model,which can be output in various formats. In the practice of the method ofthe present invention, a patient and the X-ray equipment are positionedrelative to each other. A controller is preprogrammed with a scan pathand with data corresponding to the patient. The X-ray equipment emitsand detects X-ray beams at first and second energy levels to providedensitometry output. The densitometry output is digitized and merged toprovide a tomographic model, which can be compared to predeterminedparameters unique to the patient. The model can be output in variousformats, including a visual image color-coded to depict varying dentaland orthopedic structure densities.

PRINCIPLE OBJECTS AND ADVANTAGES OF THE INVENTION

The principle objects and advantages of the present invention include:providing a dental and orthopedic diagnostic application fordensitometry; providing such an application which includes a method formodeling dental and orthopedic structure using densitometry; providingsuch a method which includes dual-energy, X-ray emission and detection;providing such a method which includes providing a color-coded outputmodel showing dental density; providing such a method which detectsincipient caries; providing such a method which is adapted for detectingdecalcification beneath the surface of the dental enamel layer;providing such a method which employs scanning X-ray techniques;providing such a method which utilizes commercially available tomographyequipment; providing such a method which detects dental fractures;providing such a method which detects dental apical abscesses; providingsuch a method which detects dental pathologies at the micron level;providing such a method which facilitates the monitoring ofdecalcification in dental structures for determining appropriatetreatment; providing such a method which is adaptable for monitoringosseointegration; providing such a method which can be practiced withrelatively minor changes to existing densitometry equipment; andproviding such a method which is economical in operation andparticularly well adapted for the proposed usage thereof.

Other objects and advantages of this invention will become apparent fromthe following description taken in conjunction with the accompanyingdrawings wherein are set forth, by way of illustration and example,certain embodiments of this invention.

The drawings constitute a part of this specification and includeexemplary embodiments of the present invention and illustrate variousobjects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, block diagram of a dental and orthopedicdensitometry modeling system embodying the present invention.

FIG. 2 is a flowchart of a dental and orthopedic densitometry modelingmethod embodying the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Introduction andEnvironment

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

II. Dental Densitometry Modeling System 2

Referring to the drawings in more detail, the reference numeral 2generally designates a dental and orthopedic densitometry modelingsystem embodying the present invention. The system 2 includes acontroller 4 with a microprocessor 6 connected to a digital memorydevice 7. The hardware components of the controller 4, i.e. themicroprocessor 6 and the memory device 7, can comprise any of a numberof suitable hardware devices which are commercially available and aresuitable for this application. In addition to various programable logicdevices (PLDs) and special-purpose microprocessors, general purpose,commercially available personal computers can be utilized in thecontroller 4. The controller 4 can be programmed in any suitable mannerutilizing any of a variety of commercially available programminglanguages and software development systems.

The microprocessor 6 is adapted to receive input from one or more inputdevices 8, such as a keyboard, a pointing device (e.g., a mouse), acommunications link, or another computer. Without limitation on thegenerality of useful data which can be input via the input device(s) 8,such data can include: 1) a patient's dental and orthopedic records,including previous tomographical densitometry models; 2) baselinetomographical densitometry models, which can be adjusted to accommodatefor such factors as age, gender, size, weight, etc.; and 3) apreprogrammed scan path for the X-ray equipment.

The microprocessor 6 controls a positioning motor 10 which is operablyconnected to X-ray equipment 12 and is adapted for moving same throughthree axes of movement. Examples of X-ray equipment adaptable for usewith the present invention are disclosed in U.S. Pat. No. 5,533,080;U.S. Pat. No. 5,838,765; and U.S. Pat. No. Re. 36,162, which areincorporated herein by reference. The X-ray equipment 12 includes anX-ray beam source 14 and a detector array 16. The X-ray beam cansuitably collimated to assume any suitable configuration, such as fan,pencil, cone, etc. With the scanning technique disclosed, a restricted(i.e. collimated) beam is preferred. The source and the detector array14, 16 are adapted for positioning on either side of a patient'sdental/orthopedic structure 18.

Analog signals from the detector array 16 are output to ananalog-to-digital (A/D) convertor 20, from which digitized signals aretransmitted to a merger device 22 for merging into formats suitable forprocessing and analyzing by the microprocessor 6. The microprocessor 6,using data from the merger device 22, creates a tomographicaldensitometry model 24 which is transmitted to an output device ordevices 26. Without limitation on the generality of useful outputdevices 26, it can comprise a monitor, a display, a printer, acommunications link, and/or another computer. For example, a colorprinter can be utilized to provide a color-coded graphicalrepresentation of the tomographical densitometry model 24. The colorcoding can correspond to densities, thus identifying potential problemareas where decalcification has occurred and resulted in lower density.The tomographical densitometry model 24 can also be useful formonitoring osseointegration, since the density of the dental/orthopedicstructure 18 (tissue and bone) in the vicinity of an implant 28 or otherprostheses can provide an important diagnostic tool for the use of thedental or medical practitioner in assessing the effectiveness of animplant or prosthetic procedure. The tomographical densitometry model 24is also entered into the computer's memory device 7.

III. Dental and Orthopedic Densitometry Modeling Method

FIG. 2 is a flow chart of a dental and orthopedic densitometry methodembodying the present invention. The method steps include positioning apatient and positioning the X-ray equipment relative to the patient,i.e. with the patient's dental/orthopedic structure to be examinedlocated between the X-ray source 14 and the detector array 16.

Diagnostic parameters are input to the system and can comprise, forexample, the patient's prior tomographical densitometry models andstandardized models. The tomographical densitometry models can becorrected and/or adjusted to account for patients' age, gender, physicalcharacteristics, etc. The input diagnostic parameters can be stored inthe computer's memory device. A scan path for the X-ray equipment ispreprogrammed in the computer.

The scanning procedure is commenced by collimating a first energy bandbeam, detecting emissions from same with a detector array, andconverting the analog output of the detector array to a digital signal.The digital signal is output for storage in the computer. The steps ofcollimating the energy band beam and detecting, digitizing and storingsame are repeated for a second energy band beam. The Bisek et al. U.S.Pat. U.S. Pat. No. Re. 36,362 discloses the use of dual-energy X-raybeams in medical densitometry applications. As discussed therein,dual-energy densitometry can result in a more accurate patient model.

The X-ray equipment then traverses the preprogrammed scan path and thefirst/second energy band steps are repeated until the scanning procedureis complete. The digitized detector array output is merged and comparedto the diagnostic parameters which are stored in the computer's memory.The dental/orthopedic densitometry is tomographically modeled andoutput, for example to a monitor or printer for converting the model toa visual image. The visual image is output in a visible form for use bydental and medical practitioners.

What is claimed and desired to be secured by Letters Patent is as follows:
 1. A system for tomographically modeling dental and orthopedic structure densitometry, which includes: a) a controller with a microprocessor and a memory device connected to the microprocessor, said controller including means for storing a pre-existing tomographical dental/orthopedic densitometry model; b) an input device connected to the microprocessor; c) a positioning motor connected to the microprocessor and movable in response to from said microprocessor; d) X-ray equipment including an X-ray source and a detector array; e) conversion means for converting a signal from said detector array, said conversion means being connected to said detector array and to said microprocessor; and f) an output device connected to said microprocessor and adapted for receiving a tomographical densitometry model from said microprocessor.
 2. The system according to claim 1 wherein said positioning motor is adapted for positioning said X-ray equipment with respect to three axes of movement.
 3. The system according to claim 1 wherein said conversion means comprises an analog-to-digital convertor connected to said detector array.
 4. The system according to claim 3 wherein said conversion means includes a merger device connected to said analog-to-digital converter and to said microprocessor.
 5. The system according to claim 1 wherein said X-ray equipment comprises a dual energy level, restricted beam device.
 6. The system according to claim 1 which includes: a) a preprogrammed scan path for said X-ray equipment, said scan path being programmed into said microprocessor.
 7. The system according to claim 1 wherein said output device includes a color monitor adapted to receive said tomographical densitometry model output color-coded to represent densitometry.
 8. The system according to claim 1 wherein said output device includes a color printer adapted to print images color-coded to correspond to the densitometry of said model.
 9. The system according to claim 1 wherein said controller includes means for comparing said pre-existing tomographical densitometry model to a current tomographical densitometry model.
 10. A method of tomographically modeling dental and orthopedic densitometry, which includes the steps of: a) providing a controller with a microprocessor and a memory device connected to said microprocessor; b) providing an input device connected to said microprocessor; c) inputting patient diagnostic parameters with said input device; d) storing said diagnostic parameters in memory; e) providing X-ray equipment with an X-ray source and an X-ray detector array; f) positioning said X-ray equipment and a patient's dental/orthopedic structure relative to each other with said patient's dental/orthopedic structure between said source and said detector array; g) emitting an X-ray beam from said source through said dental structure and to said detector array; h) outputting a signal from said detector array to said microprocessor; i) forming with said microprocessor a tomographical densitometry model of said dental/orthopedic structure; j) providing an output device connected to said microprocessor, and k) outputting said densitometry model to said output device.
 11. The method according to claim 10 which includes the additional steps of emitting, detecting, digitizing, and storing signals corresponding to first and second energy levels from said X-ray source.
 12. The method according to claim 10 which includes the additional steps of: a) inputting to said controller a predetermined scan path for said X-ray equipment; and b) traversing said X-ray equipment along said scan path.
 13. The method according to claim 12 which includes the additional steps of: a) providing a positioning motor connected to said microprocessor and to said X-ray equipment for moving same through three axes of movement along said scan path.
 14. The method according to claim 10 which includes the additional step of detecting incipient caries with said tomographical densitometry model.
 15. The method according to claim 10 which includes the additional step of detecting dental fractures with said tomographical densitometry model.
 16. The method according to claim 10 which includes the additional step of detecting apical abscesses with said tomographical densitometry model.
 17. The method according to claim 10 which includes the additional step of analyzing the extent of osseointegration of a dental or orthopedic prostheses with respect to a patient's dental or orthopedic structure with said tomographical densitometry model.
 18. The method according to claim 10 which includes the additional step of comparing said patient's current densitometry model to pre-existing densitometry model.
 19. The method according to claim 10 which includes the additional steps of: a) providing a color output device connected to said microprocessor; and b) color coding said densitometry model in colors corresponding to the patient's dental or orthopedic structure density and outputting said densitometry model to said output device.
 20. A method of tomographically modeling dental and orthopedic densitometry, which includes the steps of: a) providing a controller with a microprocessor and a memory device connected to said microprocessor; b) providing an input device connected to said microprocessor; c) inputting with said input device dental or orthopedic patient diagnostic parameters, including a pre-existing densitometry model; d) storing said diagnostic parameters in said memory device; e) providing X-ray equipment connected to said microprocessor, said equipment including an X-ray source and an X-ray detector array; f) positioning said X-ray equipment and a patient's dental or orthopedic structure relative to each other with said patient's dental or orthopedic structure located between said X-ray source and said detector array; g) emitting an X-ray beam from said source at a first X-ray beam energy level, passing same through said dental or orthopedic structure, and detecting same with said detector array; h) outputting a signal corresponding to said detected X-ray beam from said detector array; i) digitizing said detector array output signal; j) storing said digitized output signal in said memory device, k) repeating steps f)-j) at a second X-ray beam energy level; l) merging said stored output signals to form a present tomographical densitometry model of said dental or orthopedic structure; m) comparing said present densitometry model with said pre-existing densitometry model; n) adjusting said present densitometry model to account for patient parameters including age and gender; o) providing an output device connected to said microprocessor; p) color coding said present tomographical densitometry model with colors corresponding to dental or orthopedic structure density; and q) outputting said color-coded model to said output device. 